Related Clues:

• Mighty long time: Var.
• It goes on and on
• Geologic time
• Longish time span
• Time immemorial
• L-o-n-g time period
• A really long time
• Long period
• A very long time
• It's a stretch
• Eternity
• Many eras
• Years and years and years and ...
• Near-eternity
• Lo-o-ong time